Claude Fable 5$22.000/MClaude Opus 4.8$11.000/MClaude Opus 4.7$11.000/MClaude Opus 4.6$11.000/MClaude Opus 4.5$33.000/MClaude Sonnet 3.7$6.600/MClaude Opus 3$33.000/MClaude 2.1$12.800/MClaude 2$12.800/MGPT-5.5$12.500/MGPT-5.2$5.425/MGPT-5.2-Codex$5.425/MGPT-5$3.875/MGPT-4.5$97.500/MGPT-4 Turbo Preview$16.000/MGPT-4$39.000/MGPT-4-32k$78.000/Mo3$19.000/Mo3-mini$2.090/Mo4-mini$2.090/Mo1$28.500/Mo1-mini$5.700/Mo1-preview$28.500/MGemini 3.5 Pro$5.000/MGemini 3.1 Pro$5.000/MGemini 3 Pro$5.000/MGemini 2.5 Pro$3.875/MGemini 1.5 Pro$2.375/MGemini 1.0 Ultra$12.000/MGemini 1.0 Pro$0.800/MClaude Fable 5$22.000/MClaude Opus 4.8$11.000/MClaude Opus 4.7$11.000/MClaude Opus 4.6$11.000/MClaude Opus 4.5$33.000/MClaude Sonnet 3.7$6.600/MClaude Opus 3$33.000/MClaude 2.1$12.800/MClaude 2$12.800/MGPT-5.5$12.500/MGPT-5.2$5.425/MGPT-5.2-Codex$5.425/MGPT-5$3.875/MGPT-4.5$97.500/MGPT-4 Turbo Preview$16.000/MGPT-4$39.000/MGPT-4-32k$78.000/Mo3$19.000/Mo3-mini$2.090/Mo4-mini$2.090/Mo1$28.500/Mo1-mini$5.700/Mo1-preview$28.500/MGemini 3.5 Pro$5.000/MGemini 3.1 Pro$5.000/MGemini 3 Pro$5.000/MGemini 2.5 Pro$3.875/MGemini 1.5 Pro$2.375/MGemini 1.0 Ultra$12.000/MGemini 1.0 Pro$0.800/M
BETA
Subscribe
← Back to Index·All xAI models
xAI
xAIMultimodal

Grok 3 Fast

Balanced

Speed-tuned Grok 3 with vision. Trades a few quality points for faster response — useful for chat UIs that need streaming feel.

Grok 3 Fast is a multimodal AI model from xAI. It costs $5.000 per million input tokens and $25.000 per million output tokens (blended $11.000/M), with a 131K-token context window.

Modalities text, visionOfficial model page ↗Provider pricing ↗API docs ↗Compare with another model →Estimate monthly cost →
INPUT
$5.000/M
per million input tokens
OUTPUT
$25.000/M
per million output tokens
BLENDED 70/30
$11.000/M
default reference rate · how it's calculated →
CONTEXT
131K
131,000 tokens
What it's good at
  • Fast Grok 3
  • Vision-capable
  • Real-time X data
Typical use cases
  • Realtime chat UI
  • Vision QA grounded in social media
Benchmarks
vs. best public score
MMLU86%
Multitask academic knowledge across 57 subjects.
GPQA Diamond75%
Graduate-level science questions, "Google-proof".
MATH89%
High-school competition math problems.
HumanEval86%
Python function synthesis from docstrings.
LMArena Elo1332 Elo
Crowd-sourced head-to-head preference Elo rating.
Hand-curated from each provider's published reports and public leaderboards. Methodology varies across sources — treat as directional rather than authoritative.
More from xAI
See all 8 →
Grok 4.3
Frontier · 1M ctx
in $1.250/Mout $2.500/M
Grok 4
Previous · 256K ctx
in $3.000/Mout $15.000/M
Grok 3
Frontier · 131K ctx
in $3.000/Mout $15.000/M
Grok 3 mini
Efficient · 131K ctx
in $0.300/Mout $0.500/M
Grok 2
Previous · 131K ctx
in $2.000/Mout $10.000/M
Grok 2 Vision
Vision · 32K ctx
in $2.000/Mout $10.000/M
Frequently asked questions

How much does Grok 3 Fast cost?

Grok 3 Fast costs $5.000 per million input tokens and $25.000 per million output tokens, for a blended reference rate of $11.000 per million tokens.

What is Grok 3 Fast's context window?

Grok 3 Fast supports up to 131K tokens of context (131,000 tokens).

What is Grok 3 Fast best for?

Grok 3 Fast is well suited to Fast Grok 3, Vision-capable and Real-time X data.

Who makes Grok 3 Fast?

Grok 3 Fast is developed and served by xAI.